An installer manages the installation of software packages on a computer, manages the additions and deletions of software components, monitors file resiliency, and maintains basic disaster recovery by using rollbacks.
A rollback typically involves utilizing a snapshot of the computer's file system. The snapshot is captured prior to installation of a software package. If the software package is not installed successfully, the snapshot may be used to restore the file system to the state prior to the installation.
An installer may be customized. However, a poorly designed customization can result in files being installed in incorrect locations. A poorly designed customization can go undetected.
A malicious customization can result in existing files on the computer being moved, deleted or replaced. Valuable data can be lost, control of the computer can be compromised, and system stability can be affected. A malicious customization can go undetected.